Publications by authors named "Eike Volkmann"

Functional bone and dental implant materials are required to guide cell response, offering cues that provide specific instructions to cells at the implant/tissue interface while maintaining full biocompatibility as well as the desired structural requirements and functions. In this work we investigate the influence of covalently immobilized alkaline phosphatase (ALP), an enzyme involved in bone mineralization, on the first contact and initial cell adhesion. To this end, ALP is covalently immobilized by carbodiimide-mediated chemoligation on two highly bioinert ceramics, alpha-alumina (Al2O3) and yttria-stabilized zirconia (Y-TZP) that are well-established for load-bearing applications.

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An important challenge in the field of dental and orthopedic implantology is the preparation of implant coatings with bioactive functions that feature a high mechanical stability and at the same time mimic structural and compositional properties of native bone for a better bone ingrowth. This study investigates the influence of magnesium addition to zirconia-calcium phosphate coatings. The mixed coatings were prepared with varying additions of either magnesium oxide or magnesium fluoride to yttria-stabilized zirconia and hydroxyapatite.

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Enhanced coating stability and adhesion are essential for long-term success of orthopedic and dental implants. In this study, the effect of coating composition on mechanical, physico-chemical and biological properties of coated zirconia specimens is investigated. Zirconia discs and dental screw implants are coated using the wet powder spraying (WPS) technique.

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In this study a bioinspired approach to induce self-mineralization of bone-like material on alumina surfaces is presented. The mineralizing enzyme alkaline phosphatase (ALP) is covalently immobilized by a carbodiimide-mediated chemoligation method. The enzymatic activity of immobilized ALP and its mineralization capability are investigated under acellular conditions as well as in the presence of human bone cells.

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Ca3ZrSi2O9 (baghdadite) has become a major research focus within the biomaterial community due to its remarkable in-vitro and in-vivo bioactivity. Although baghdadite seems to exhibit interesting biological properties, as yet there has been no data published concerning its mechanical properties. This lack of knowledge hinders targeting this novel bioactive material towards potential applications.

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Purpose: Yttria-stabilized zirconia (TZ) is used for dental applications because of its low toxicity and beneficial mechanical properties, but it does not stimulate bone regeneration around the implant due to its bioinertness. Therefore, hydroxyapatite (HA) coatings are often utilized to increase the surface bioactivity and to achieve a better osseointegration. These coatings, however, are chemically nonstable and provide a weak bonding to the substrate surface.

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The current opinion on the toxicity of nanomaterials converges on a size-dependent phenomenon showing increasing toxicity with decreasing particle sizes. We demonstrate that SiO2 particles have no or only a mild effect on the viability of five bacterial strains, independently from the particle size. A two-hour exposure to 20 mg L(-1) of 15, 50 and 500 nm sized SiO2 particles neither alters bacterial adenosine triphosphate (ATP) levels nor reduces the number of colony forming units (CFU).

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